scholarly journals Research on Aircraft Surface Taxi Path Planning and Conflict Detection and Resolution

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Ningning Zhao ◽  
Nan Li ◽  
Yu Sun ◽  
Lei Zhang
Keyword(s):  
Time Window ◽  
Time Windows ◽  
Conflict Detection ◽  
Real Time Control ◽  
A Algorithm ◽  
Use Of Time ◽  
Time Control ◽  
Control Decision ◽  
The Difference ◽  
Glide Paths

Aircraft surface taxiing conflict avoidance is mostly adopted by waiting and rerouting methods, but this method does not consider the difference in total taxiing time that may be caused by different strategies. In this study, the airport taxiing path optimization model and taxiing area division model are constructed first. Then, the taxiway use is controlled by subregion based on the analysis of the surface activity area connection relationship. Based on the results of aircraft surface taxiway preselection, the time window of the taxiing area is solved and conflict detection is performed. For aircraft with taxiing conflicts, waiting or changing paths is selected to deconflict taxiing by comparing priorities. An improved A∗ algorithm solution is applied to generate conflict-free glide paths and new glide trajectory occupancy time windows, while the glide paths of aircraft without glide conflicts are not affected. The results of the study show that the use of time windows for conflict detection and deconfliction can further reduce the total taxiing time of aircraft operating on the surface, resulting in a significant reduction in the number of aircraft conflicts, and thus, airport operational safety is ensured. This study has a high practical value and is expected to be applied in the real-time control decision of aircraft taxiing in the future.

In-Cycle Closed Loop Control of the Fuel Injection on a 1-Cylinder Heavy Duty CI-Engine

2010 ◽  
Author(s):  
Claes-Go¨ran Zander ◽  
Per Tunesta˚l ◽  
Ola Stenla˚a˚s ◽  
Bengt Johansson
Keyword(s):  
Heat Release ◽  
Real Time ◽  
Fuel Injection ◽  
Real Time Control ◽  
Loop Control ◽  
Time Control ◽  
Ci Engine ◽  
The Difference ◽  
Proportional Controller ◽  
Polytropic Exponent

The focus of this article is on implementation of real time combustion control by using an FPGA. The feedback used for the controller is the heat release. Due to the desire to avoid using division on the FPGA an alternative way of calculating the polytropic exponent is investigated. When this method is compared against using a constant exponent it shows less fluctuations in regards to cycle to cycle variations when calculating the heat release. A dual injection strategy is used and real time control is implemented on the second fuel injection. The calculated heat release is continuously compared with a reference and then the difference is converted to a duration correction of the fuel injection. This is done by a proportional controller which is initiated after the start of the second injection. By adding a perturbation on the first fuel injection the controller is shown to compensate during the second and thereby decreasing the cycle to cycle variations.

scholarly journals Control of a Prosthetic Arm Using fNIRS, a Neural-Machine Interface

2020 ◽  
Author(s):  
Usama Ali Syed ◽  
Zareena Kausar ◽  
Neelum Yousaf Sattar
Keyword(s):  
Real Time ◽  
Near Infrared ◽  
Time Window ◽  
Time Signal ◽  
Real Time Control ◽  
Functional Near Infrared Spectroscopy ◽  
Prosthetic Devices ◽  
Linear Discriminant ◽  
Time Control ◽  
Artificial Neural Network Ann

Development in the field of bio-mechatronics has provided diverse ways to mimic and improve the function of human limbs. Without an elbow joint, the hand remains stiff because all the muscles tension passes through this joint. Advanced myoelectric prosthetic devices are limited due to the lack of appropriate signal sources on residual amputee muscles and insufficient real-time control. Neural-machine interfaces (NMI) are representing a recent approach to develop effective applications. In this research study, an NMI is designed that presents real-time signal processing for command generation. The human brain hemodynamic responses are, therefore, translated into control commands for people suffering from transhumeral amputation. A novel and first of its kind scheme is proposed which utilizes functional near-infrared spectroscopy (fNIRS) to generate the control commands for a three-degree-of-freedom (DOF) prosthetic arm. The time window for fNIRS signals was set to 1 second. The average accuracy was found to be 82% which is a state-of-the-art result for such a technique. The accuracy ranged from 65 to 85% subject-wise. The data were trained and tested on both artificial neural network (ANN) and linear discriminant analysis (LDA). Eight out of 10 motions were correctly predicted in real time by both classifiers.

A Model to Assess the Performance of Controlled Urban Drainage Systems

1994 ◽  
Vol 29 (1-2) ◽  
pp. 437-444 ◽  
Author(s):  
Fons Nelen
Keyword(s):  
Real Time ◽  
Storage Capacity ◽  
Drainage System ◽  
Urban Drainage ◽  
Real Time Control ◽  
Drainage Systems ◽  
Time Control ◽  
Controlled Systems ◽  
Urban Drainage Systems ◽  
The Difference

The LOCUS modelling package, which has been designed to assess the performance of an urban drainage system that is controlled in real time is presented. Besides the simulation of 'optimal' controlled systems, LOCUS offers the possibility to simulate local (or static) controlled systems as well (i.e. the present way of operation of most urban drainage systems). Since an identical system description is used in both cases, the difference between the results is only due to the way the system is operated and hence the effects of real time control can be quantified by comparing the results. The use of the model is illustrated by a simple example, which shows that it is worth investigating the potential of real time control before constructing extra storage in the system. For a small fictitious system with limited storage capacity at the downstream section it is shown that this potential is comparable to increasing the storage capacity by 1.5 mm at this particular section.

The effect of the crust on the estimation of mantle Q from spectral ratios of multiple ScS phases

1997 ◽  
Vol 87 (3) ◽  
pp. 778-781
Author(s):  
Takehi Isse ◽  
Ichiro Nakanishi
Keyword(s):  
Background Noise ◽  
Numerical Experiments ◽  
Time Window ◽  
Time Windows ◽  
Specific Time ◽  
Spectral Ratios ◽  
Arrival Times ◽  
Numerical Tests ◽  
Error Bars ◽  
The Difference

Abstract To estimate Qscs, previous studies used the spectral ratios of multiple ScS phases calculated for specific time windows. They assumed that the spectral ratios had linear relation with frequency. However, the spectral ratios very often did not seem to be linear, and the error bars were very large for frequencies higher than about 0.05 Hz. We have performed numerical experiments to search for the cause of these anomalies and found that they are caused by the multiple reflection in the crust under the surface bounce point of ScS2. A method of suppressing the anomalies is to start the time of the time window at 40 sec prior to the theoretical arrival times of the multiple ScS phases. In numerical tests, the difference between the correct and estimated values of Qscs is only 0 to 5% using this method, but it is 10 to 50% in the conventional method. We find that the crustal effect is more important in the estimation of Qscs than background noise, which has been readily handled in previous studies using standard stacking techniques.

La simulation assistée par ordinateur dans le contrôle et l'utilisation optimale des ressources hydriques

1992 ◽  
Vol 19 (3) ◽  
pp. 432-440
Author(s):  
N. Serhir ◽  
C. Marche
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Power Plants ◽  
Real Time Control ◽  
Water Resource System ◽  
Time Step ◽  
Model Builder ◽  
Use Of Time ◽  
Time Control ◽  
Element Method

Simulators are gradually becoming popular in hydraulic engineering. They allow real-time control of hydroelectric projects, help operators optimize facilities, and are excellent for training technical staff. This paper shows how to constitute a specialized simulator for each water resource system using a model builder and a set of site data. The model builder is based on digitization by finite element method. Resolution without linking is applied, allowing use of time-step variables. Each simulator constituted can operate in controlled or uncontrolled mode. An example illustrates the search for optimum generation mode for a network composed of three power plants. Key words: simulator, hydroelectricity, finite element method. [Journal translation]

A Subway Train Timetable Optimization Approach Based on Energy-Efficient Operation Strategy

2012 ◽  
Author(s):  
Shuai Su ◽  
Xiang Li ◽  
Tao Tang
Keyword(s):  
Energy Efficient ◽  
Optimization Approach ◽  
Energy Prices ◽  
Real Time Control ◽  
Speed Limits ◽  
Efficient Operation ◽  
Time Control ◽  
Trip Time ◽  
The Difference ◽  
Automatic Train Operation

With the rising energy prices and environment concerns, energy-efficient operation is paid more and more attention in the subway systems, which is one of the effective ways to reduce the operation cost and then improve the operation efficiency. There are many researches for energy-efficient operation on designing a reasonable timetable or optimizing the speed profile, but all of them are studied separately. To achieve a better performance on energy saving, we present an integrated algorithm for optimizing the timetable for the entire route together with the speed profiles between successive stations, which is named as integrated timetable. First, we give an analytical algorithm to get the optimal switching points for each section by using the Pontryagin maximum principle. For dealing with the variable speed limits, we calculate the reserve time, i.e., the difference between the pre-determined trip time and the minimum trip time, and then design an algorithm to distribute it among different sections with constant speed limits. Finally, we extend the algorithm to solve the integrated timetable. We also give some numerical examples to illustrate the validity of the algorithm based on the data from the Beijing YiZhuang subway line in China. It is recorded that the energy consumption for interstation trip can be reduced by 10.3% on average, and the total energy reduction for the entire trip is 14.5% by using the integrated timetable. Besides, it takes about 0.15 seconds to generate the integrated timetable, which means that the algorithm is quick enough to be used in the automatic train operation (ATO) system for real-time control.

Dynamic Design of Sewer Detention Tanks

1993 ◽  
Vol 27 (5-6) ◽  
pp. 133-143
Author(s):  
H. van Luijtelaar ◽  
P. P. G. Ganzevles
Keyword(s):  
Time Series ◽  
Design Method ◽  
Real Time Control ◽  
Combined Sewer Overflows ◽  
Dynamic Design ◽  
Frequency Distributions ◽  
Continuous Simulation ◽  
Use Of Time ◽  
Time Control ◽  
Current Design

In the Netherlands new regulations regarding combined sewer overflows have been proposed to reduce the pollution of surface water. These regulations will lead to the construction of ancillary sewer facilities. The current design methods are not suitable for optimizing measures to control overflow loads. Therefore a new method, called ‘Dynamic Design', is proposed. This design method is based upon the use of time series of rainfall and advanced computer programs. By using longterm continuous simulation in combination with historical time series of rainfall overflow volumes, discharge durations and frequencies can be derived. These results can be analysed statistically to obtain frequency distributions of overflow volumes and discharge flows. This procedure ensures not only the assessment of detention tanks but also the evaluation of alternative measures like real time control and flow routing strategies. Dynamic design aims at the efficient use of ancillary sewer facilities to minimise receiving water impact. Several cases are discussed to show the advantages of dynamic design in comparison with current design procedures.

Cordon-Based Pricing Schemes for Mixed Urban-Freeway Networks using Macroscopic Fundamental Diagrams

2021 ◽  
pp. 036119812110159
Author(s):  
Xuting Wang ◽  
Vikash V. Gayah
Keyword(s):  
Control Strategies ◽  
User Equilibrium ◽  
Real Time Control ◽  
Urban Networks ◽  
Time Control ◽  
The Difference ◽  
Freeway Networks ◽  
Mixed Networks ◽  
Urban Freeway ◽  
Pricing Schemes

The development of traffic models based on macroscopic fundamental diagrams (MFD) enables many real-time control strategies for urban networks, including cordon-based pricing schemes. However, most existing MFD-based pricing strategies are designed only to optimize the traffic-related performance, without considering the revenue collected by operators. In this study, we investigate cordon-based pricing schemes for mixed networks with urban networks and freeways. In this system, heterogeneous commuters choose their routes based on the user equilibrium principle. There are two types of operational objective for operating urban networks: (1) to optimize the urban network’s performance, that is, to maximize the outflux; and (2) to maximize the revenue for operators. To compare those two objectives, we first apply feedback control to design pricing schemes to optimize the urban network’s performance. Then, we formulate an optimal control problem to obtain the revenue-maximization pricing scheme. With numerical examples, we illustrate the difference between those pricing schemes.

A Real Time Control Architecture for Continuously Managing Patients in a Care Unit

1995 ◽  
Vol 34 (05) ◽  
pp. 475-488
Author(s):  
B. Seroussi ◽  
J. F. Boisvieux ◽  
V. Morice
Keyword(s):  
Real Time ◽  
Linear Time ◽  
Treatment Plan ◽  
Control Architecture ◽  
Real Time Control ◽  
Time Representation ◽  
Time Control ◽  
Continuous Support ◽  
Definition Of ◽  
Computerized System

Abstract:The monitoring and treatment of patients in a care unit is a complex task in which even the most experienced clinicians can make errors. A hemato-oncology department in which patients undergo chemotherapy asked for a computerized system able to provide intelligent and continuous support in this task. One issue in building such a system is the definition of a control architecture able to manage, in real time, a treatment plan containing prescriptions and protocols in which temporal constraints are expressed in various ways, that is, which supervises the treatment, including controlling the timely execution of prescriptions and suggesting modifications to the plan according to the patient’s evolving condition. The system to solve these issues, called SEPIA, has to manage the dynamic, processes involved in patient care. Its role is to generate, in real time, commands for the patient’s care (execution of tests, administration of drugs) from a plan, and to monitor the patient’s state so that it may propose actions updating the plan. The necessity of an explicit time representation is shown. We propose using a linear time structure towards the past, with precise and absolute dates, open towards the future, and with imprecise and relative dates. Temporal relative scales are introduced to facilitate knowledge representation and access.

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